As personal computers have become more popular in everyday life, they have also become more indispensable in the daily activities of a computer user. As such, many computer users desire almost constant access to their computers. As technology and communications advance and more goods and services are available through the use of a computer, such as over the Internet, the desire for constant access will continue to increase among computer users.
Conventionally, computers utilized by individuals and businesses are stand-alone devices which are generally permanently placed on a desk top, table top, or other support surface. While they may be readily moved from place to place, they are not meant to be constantly carried around by the user. To address the need for portability, portable computers are available which are carried by the user, generally in a specially made suitcase or bag. Existing portable computers continue to decrease in size and weight, but are still designed to be carried like luggage in a separate bag or other container and are then used by placing them on an available flat surface, such as a desk top.
Recently, wearable computers have become available. Wearable computers, such as a wearable personal computer, are worn or carried, and also used, on the body of the user. Therefore, the wearable computer is usually carried around without having to be stowed in a bag and hand-carried like luggage. Furthermore, a wearable computer is more likely to be used while being worn, rather than being taken off and placed on a support surface. This arrangement provides the user with greater mobility, convenience, and flexibility in the use of their computer.
As may be appreciated, a wearable computer that is worn or supported on the body of a user is thus going to be exposed to the movements of the user's body and the forces generated by such movements. Usually such forces will be predominantly those forces and accelerations encountered by the body during locomotion, such as walking and running. Such forces may be considerable, particularly if the user is running while wearing the computer. For example, an average person running will generate a ground reaction force which is around 2.4 times the person's body weight. This may result in an average acceleration of about 2 G or greater on the body and computer, and peak accelerations will frequently exceed that value. These forces, which a wearable computer must handle, can cause problems in the operation of the computer and degrade its performance.
Specifically, various electromechanical devices utilized in a computer, most notably the disk drive, are sensitive to the shock and vibration caused by motion forces. The heads of the disk drive, which are precisely positioned and aligned over selected tracks on a disk, are particularly sensitive to misalignment due to such shock and vibration. This causes operational errors, such as read errors and/or write inhibits. The orientation of a disk drive in a wearable computer only exacerbates the problem. The thinnest dimension in a computer is the plane of rotation of the disks and the head actuator. Since the wearable computer must be kept thin, the worst case accelerations and forces caused by motion, such as walking, jogging, or running, will be in the rotational plane of the disk drive.
Disk drive operations are severely impacted during use due to the accelerations of the user's motion which are rotational and y-axis (i.e., in the direction of the actuator) and which exceed 2 Gs. Such forces tend to cause servo tracking errors and the resulting read errors and write inhibits. The forces from such motion and accelerations actually act on the actuator arm, causing the heads of the drive to move off track. Typical track densities are over 30,000 tracks per inch in miniature (1″) disk drives. Therefore, It may be readily appreciated that a vibration sufficient to cause 2 G acceleration will displace the heads from the desired task sufficiently to cause a write inhibit or other errors, such as read errors.
The operation of the disk drive is critical to the overall performance of any computer, including a wearable computer. Therefore, the motion forces encountered by a wearable computer, or another computer subjected to motion forces, present a significant issue with respect to the use of such a computer.
Therefore, it is an objective of the present invention to improve the overall performance characteristics of a computer subjected to motion, such as a wearable computer.
It is a specific objective to address the forces and accelerations on a wearable computer which are due to the motion of the wearer.
It is another objective of the present invention to improve the operation of a disk drive device in a computer, such as a wearable computer.
These objectives and other objectives will be more readily apparent from the further description of the of the invention below.